The present invention relates to electrode plate structures, particularly to electrode plates suitable for use in electrochemical cells such as lead acid batteries.
The capacity of a lead acid battery, such as those in common use in automobiles, is related to the surface area of electrode plate accessible to the electrolyte. While a simple lead acid battery can be made using solid lead for one electrode, and oxidized solid lead for another electrode, such a battery has very little capacity, because the surface area of the electrodes in contact with the electrolyte is relatively small, so that the electrochemical reaction that occurs does so on a small scale, relatively slowly.
A major innovation in battery plate design was the development of the pasted electrode. In this design, particles of lead or lead oxide are held in a porous matrix of binder material. The electrolyte is permitted to permeate the matrix, and simultaneously contact a large number of particles, having a correspondingly large surface area. As a result, the magnitude of the electrochemical reaction occurring in the electrodes is much greater.
In the pasted plate electrode, a grid or restraining base is used, upon which is pasted active material which consists of porous "active mass." Electrolyte penetrates this mass by diffusion processes. The penetration of the mass by the aqueous electrolyte is restricted by the porosity of the active mass.
Unfortunately, there are limitation on the rate at which electrolyte can penetrate the active mass, to permit continuance of the electrochemical reactions in the plate at an optimum rate. An increase in the flow of electrolyte through and around the active mass would have a significant impact on the performance of the battery.
Accordingly, it is an object of the present invention to provide an electrode plate structure that provides increased battery capacity.
A further object of the present invention is to provide an electrode plate structure that simplifies the manufacturing process for such plates.
An object of an alternative embodiment of the present invention is to provide a pasted electrode plate structure that has a greater capacity than conventional pasted plates.
Yet another object of the present invention is to provide an electrode plate having a high surface area that uses capillary action and/or enhanced diffusion processes to facilitate contact between the active mass and the electrolyte, thereby increasing the capacity of the battery.
These and other objects of the present invention can be appreciated by reference to the detailed discussion that follows, together with the appended drawings.